Sprung mounted snubber wear plate

ABSTRACT

A sprung wear plate particularly useful for reliable secure application to the side frame columns of a railway truck is made from a single metal strip having a concave surface facing the flat mounting surface on the side frame column. The plate has holes for attachment by bolts through aligned holes in the column. High strength bolts are used such that tightening of the bolts flattens out the concave surface of plate into full contact with the column locking the bolts therein. The bolts preferably have tapered heads received in tapered holes in the plates to prevent accidental application of the plates with the concave surface facing outwardly.

United States Patent 1191 [111 3,834,320

Tack 1451 Sept. 10,1974

[ 1 SPRUNG MOUNTED SNUBBER WEAR 3,714,905 2/1973 Barber 105/197 DB PLATEPrimary Examiner-M. Henson Wood, Jr. [75] Inventor. Carl E. Tack,Elmhurst, 11]. Assistant Examiner Howard Beltran [73] Assignee: TransDyne, Inc., Chicago, Ill. Attorney, Agent, or Firm-Gary, Juettner,Pigott & 22 Filed: Jan. 5, 1973 Gunman [21] App]. No.: 321,131 I 57ABSTRACT I A sprung wear plate particularly useful for reliable sell05/197 7 29/522, cure application to the side frame columns of a rail-105/19 105/20 188/250 G waytruck is made from a single metal striphaving a 1111- Cl 1361f 1361f F16d 69/04 concave surface facing the flatmounting surface on Field of Search 197 the side frame column. The platehas holes for attach- 1 7 188/250 G ment by bolts through aligned holesin the column.

' High strength bolts are used such that tightening of 1 ReferencesCited the bolts flattens out the concave surface of plate into UNITEDSTATES PATENTS full contact with the column locking the bolts therein.1,939,553 12/1933 The bolts preferably have tapered heads received in2,169,715 3/1939 tapered holes in the plates to prevent accidentalappli- 2,237,953 4 1941 cation of the plates with the concave surfacefacing 3,230,152 H1966 outwardly. 3,362,449 l/1968 3,548,754 12/1970Williams 105/197 D a 7 Chims, 4 Drawing Figures SPRUNG MOUNTED SNUBBERWEAR PLATE BACKGROUND OF THE INVENTION Wear plates are employed inrailway and other industries as a replaceable part that is subject tofriction, rubbing or abrasion from another part. A wear plate isbeneficially used on a large or expensive casting having one or moresurfaces that are exposed to frictional deterioration. By securing aremovable wear plate over such exposed surfaces, any wear will beconfined to the plate and not to the casting, thereby extending the lifeof the casting indefinitely with the simple replacement of wear plates.I

A long unresolved problem in the railway industry is a reliable means ofsecuring a wear plate to the side frame column without the platebecoming loose under service conditions. In that application, the sideframes of a railway truck have windows therein for receiving the ends ofa bolster, with the ends of the bolster being supported upon springs inthe side frame. The bolster carries a friction shoe on both sides thatis urged by a spring against a vertical column located at each side ofthe side frame window. Frictional engagement of the friction shoeagainst the column locking the bolts therein serves to dampen suddenvertical movement of the bolster, which in turn stabilizes the travel orride of therailway vehicle.

Since the side frame is a heavy and relatively expensive member,friction plates are commonly secured against the side frame columns toconfine frictional wear to the plates and prevent permanent damage tothe side frame. Various methods have been proposed to secure the wearplates, including welding. and bolt-' ing, but none of these methodsalone have proven to be successful in achieving permanent securement forall side frames and service conditions. Under service conditions,especially with the advent of heavier and faster vehicles, a weldedjoint tends to develop cracks and may eventually break. Boltedconnections, including both threaded connections and lockbolts appliedwith an impact device, have failed to adequately solve the problem sincein many instances the wear plates'become loose after a period of time.

The experience within the railway industry indicates that it would bedesirable to devise a highly reliable and yet inexpensive means forsecuring wear plates in such a manner that they would not become looseor fall off under severe and continued service conditions. The looseningof a friction plate can result in various problems, the most serious ofwhich are permanent damage to the columns or friction shoes, or in caseof a lost plate, loss of ride control in the truck.

Existing wear plates are required by A.A.R. standards to be flat, with apossible tolerance in either direction of 0.025 inches. The cast columnsurfaces to which the wear plates are attached are also designed to beflat, but experience has shown that such surfaces may vary from 0.025inches concave to 0.010 inches convex. All efforts have been directed toestablishing a flat, smooth interface to achieve full contact betweenthe facing members before they are secured together.

SUMMARY OF THE INVENTION In accordance with the present invention, thewear plate is curved or shaped into a predetermined form prior to itsapplication to the side frame column. I have found that the wear platebecomes loose because the allowable tolerance may permit only partialcontact and may result in a situation where the facing surface of theplate is spaced from the column surface in one or more areas. Underheavy pressure, the plate is able to flex slightly, which eventuallycauses wearing of contacting surfaces or loosening of the bolts or othersecurement means.

The present invention provides a wear plate which is initially formedwith a concave surface facing the side frame column. The concavity ofthe plate or plate surface is designed to be greater than any normal orabnormal variation from flatness in the column surface, in order toassure that the central portion of the plate surface will be initiallyspaced from the column surface while .the outer perimeter of the platesurface will contact the column surface.

The central portion of the plate surface is then drawn into full contactwith the column surface with heavy threaded bolts and nuts passingthrough the plate and column. Since the plate has characteristics of aspring, two heavy bolts are employed and are-alternately tightened untilthe spring force of the plate ismet or exceeded and the central portionof the plate fully engages the column. I Upon application, the wearplate takes advantage of the spring forces generated during itsattachment, and the edges of the plate conform to any variation fromflatness in the column surface. Loads on the wear plate therefore tendto be distributed evenly, and the tendency of the plate to flex or rockon the column'is greatly minimized.

THE DRAWINGS FIG. 3 is 'a'fragmentary sectional. view taken alongsection line 33 of FIG. 1; and

FIG. 4 is a fragmentary sectional view taken substantially along sectionline 4-4 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The principles of the presentinvention will be described in connection with a friction platel0'adapted to be mounted on a side frame 12 of a railway truck as shownin FIG. 1, but it shall be understood that the invention hasapplicability to other-forms of plates secured in other locations, aswill be readily apparent to those skilled in this and related arts. Theside frame 12 is conventional in nature and generally comprises an uppercompression member 14 and alower tension member 16 having a spring seat18 formed therein for support of spring groups that resiliently supportthe end of the bolster (not shown). A vertical column 20 extends betweenthe tension and compression members and has an inwardly facing surface22 upon which the friction plate 10 is supported and carried. Spacedlugs 24 may be provided on the column surface to locate and maintain thefriction plate in proper position on the column.

Since only a portion of the truck is shown for the sake of brevity, itwill be understood that a second column is connected between thecompression and tension members in parallel relation to the first, andthe second column is also provided with an inwardly facing surfacecarrying a friction plate. The friction plates in each side frametherefore face one another and serve as frictional surfaces for slidingengagement by friction shoes carried by the bolster.

As shown in FIGS. 2, 3 and 4, the column surface 22 is designed to besubstantially flat within standard tolerances established by theindustry. The friction plate, however, is provided with a curvedconfiguration, with the surface 36 facing the column surface 22 having aconcave curvature. A pair of vertically spaced apertures 26 are providedin the generally rectangular plate 20 for attachment by bolts 28 andnuts 30 to the side frame column. The apertures are countersunk ortapered inwardly at 32 from the outwardly facing surface 34 of theplate, and the heads of the bolts 28 are similarly tapered but of lesswidth than the length of the tapered areas 32, such that the head of thebolt, when seated, will be spaced inward from the outer surface 34.

The friction plates of the present invention are preferably made fromresilient steel plate or strip stock. The strength and wearcharacteristics of the metal are improved by heating and quenching, withsubsequent heating to a lower temperature to control hardness. Theseprocedures are commonly employed by the industry in the manufacture offlat plates, all of which steps make it difficult, if not impossible toachieve and hold a small tolerance on flatness.

In addition to the foregoing, the friction plates are given the desireddegree of curvature as shown during or after routine processing.Curvature may be imparted to the plate while hot by forming on a die,or. a shaping die may be employed while the apertures 26 are beingpunched. In the alternative, after final tempering the plate may beshotpeened on one side, which will cause it to curl in the desiredamount and direction. Other well known methods may be employed toachieve the same result, and the above should be considered as onlyexemplary.

An important feature of the present invention is the means by whichproper and fool-proof installation of the friction plate is achieved.Installation with the concave surface facing outwardly would defeat thepurpose of the invention. For this reason, the apertures 26 taper inwardfrom the convex outer surface 34, and this feature assures that theconcave surface 36 will also face the column upon installation.

The ends of the present invention may be achieved if the plate is formedwith curvature about either a vertical or horizontal axis, or with acompound curvature, but in the preferred embodiment, the plate is formedwith a spherical curvature as shown in FIGS. 3 and 4. The plate may becurved along its entire width, or the majority of the curvature may beconfined to the central portion of the plate, with the outer perimeterof the surface being substantially flat. In the case of wear plates forcolumns, a spherical radius between about 9 to about 15 inches,preferably in the order of about 12 inches, will be sufficient toachieve the desired degree of curvature. The friction plate willgenerally measure 8 to 10 inches long, 4 to 7 inches wide, andapproximately A; to inches thick. The degree of curvature should in anyevent be greater than the maximum convex curvature expected in thefacing part, such that the central portion of the plate will be spacedfrom the facing surface before the bolts are tightened.

The relation of the wear plate to the column is shown in FIGS. 3 and 4,and it may be seen that the central portion of the plate is slightlyspaced from the facing column surface with the bolts applied but nottight. The bolts are then tightened alternately until the centralportion of the plate is drawn up against the column surface. Theapertures 26 must be located toward the center of the plate in order toassure deflection when the nuts are tightened. It will be understoodthat a sufficiently heavy bolt must be employed to fully deflect theplate into contact position. We have found that a 34 by 2 inch grade 8bolt having a high strength self-locking nut which is torqued to 175 to200 ft. -lbs., will fully deflect the plate, although bolts of lowergrades might possibly be used.

I claim:

1. In a railway truck having side frames, each side frame comprisingvertical columns with wear plates secured on the inwardly facingsurfaces thereof, said column surfaces being substantially flat, theimprovement wherein the wear plate has a concave shape relative to andfacing said column surface, and securement means for securing anddeflecting said plate into substantially full contact with said surface,said wear plate, upon securement, being spring-loaded against saidcolumn surface.

2. The improvement of claim 1 wherein said securement means comprisevertically spaced threaded fasteners secured through apertures in saidplate and column.

3. The improvement of claim 2 wherein said apertures and the heads ofsaid bolts have similar tapered surfaces and said apertures receive saidheads.

4. The improvement of claim 2 wherein said apertures are spaced inwardfrom the sides of said plate.

5. The improvement of claim 1 wherein said wear plate is generallyrectangular and said concave shape is in the form of a sphericalcurvature.

6. Wear means adapted to be secured against the surface of a supportcomprising a resilient metal wear plate having a surface facing saidsupport surface, which, when in unstressed engagement therewith, isconcave relative thereto with a central portion of said plate surfacebeing spaced from said support surface, and securement means for drawingsaid central portion substantially against said support surface, saidwear plate, upon securement, being spring loaded against said supportsurface.

7. The wear plate of claim 6 wherein said plate is formed with aspherical curvature. k

1. In a railway truck having side frames, each side frame comprisingvertical columns with wear plates secured on the inwardly facingsurfaces thereof, said column surfaces being substantially flat, theimprovement wherein the wear plate has a concave shape relative to andfacing said column surface, and securement means for securing anddeflecting said plate into substantially full contact with said surface,said wear plate, upon securement, being spring-loaded against saidcolumn surface.
 2. The improvement of claim 1 wherein said securementmeans comprise vertically spaced threaded fasteners secured throughapertures in said plate and column.
 3. The improvement of claim 2wherein said apertures and the heads of said bolts have similar taperedsurfaces and said apertures receive said heads.
 4. The improvement ofclaim 2 wherein said apertures are spaced inward from the sides of saidplate.
 5. The improvement of claim 1 wherein said wear plate isgenerally rectangular and said concave shape is in the form of aspherical curvature.
 6. Wear means adapted to be secured against thesurface of a support comprising a resilient metal wear plate having asurface facing said support surface, which, when in unstressedengagement therewith, is concave relative thereto with a central portionof said plate surface being spaced from said support surface, andsecurement means for drawing said central portion substantially againstsaid support surface, said wear plate, upon securement, being springloaded against said support surface.
 7. The wear plate of claim 6wherein said plate is formed with a spherical curvature.